Apparatus for cutting paper sheets



June 29, 1943. R 2,323,003

APPARATUS FOR CUTTING PAPER SHEETS Filed Feb. 28, 1941 2 sheets-sheet;

INVENTOR Fall! 3410' 6. fyw

ATTORNEY Patented June 29, 1943 APPARATUS FOR CUTTING PAPER SHEETS PaulBaur, Heidenhelm-on-the-Bren z, Germany; vested in the Alien PropertyCustodian Application February 28, 1941, Serial No. 381,015 In GermanyOctober 6, 1939 3 Claims. (01. 164-45) The invention relates toapparatus for cutting paper sheets into strips, by means of circularknives, usually known as a paper slitter.

Heretofore, the paper sheet would automatically rotate two rotatableknives, by the knife peripheries following the sheet of paper. In othercases, electric motors were applied to one set of the shafts of the discknives. Both of these forms had many disadvantages, and the object ofthe present invention is to overcome the same.

The invention consists in providing means for rotating the paper cuttingknife with a velocity directly dependent upon the circumferentialvelocity of the paper sheet roll as it is being wound.

The invention may be carried out in various embodiments, one of which isto provide the shaft of the knives with a roller, and disposetransmission means between that roller and the paperroll, with means foradjustment of said transmission means.

In each of the embodiments, a method of slitting paper is utilized whichconsists in subjecting a rotary knife to a velocity in direct ratio tothe velocity of the paper sheet being wound on its roller after havingbeen slit.

The invention will be further described hereinafter, an embodiment shownin the drawings, and the invention will be finally pointed out in theclaims.

In the accompanying drawings,

Fig. J. shows a sectional view, partly diagrammatic;

. Fig. 2 shows a front view, and

Fig. 3 shows a detail view of the adjusting means.

Similar characters of reference indicate corresponding parts throughoutthe various views.

Referring to the drawings, the paper sheet I travels in the direction ofthe arrow la, along the sled l U and over the pressure roller 3, and isthen wound upon the roll shaft 2b, which rotates in the direction of thearrow 2a, and increases in circumference as the sheet is wound thereon.The roller 3 rotates in the direction of the arrow 3a, and is capable ofidling depending on the amount of paper wound upon the shaft 2b, in themanner well known. The paper sheet passes between the circular knives 4and 5, and is cut into strips thereby, depending in width upon the spacebetween the knives, in the manner well known. The knife 4 is suitablysupported by the shaft la and by bearings therefor not shown, and alsoknown. The knife 5 is supported on the shaft 1. The shaft 1 is suitablysupported by yokes l, which are supported by a carrier 8a,

having dovetail connections with a fixed support 9, secured to the sledIll.

The improved device consists of the following. To the shaft I of theknife 5 is secured a roller 6, which rotates at all times at the samespeed as that of the knife 5. Between the roller 6 and the pressureroller 3, is placed a roller ll,movable in the direction of the arrow Ila. It is supported by a shaft lib, to each end of which a link He isconnected, these links llc having a crossbar lld and at right angles tothis crossbar lid is the adjustment device I2. This has a spring 20interposed between a shoulder 20a on a rod 2|, which is secured to thecrossbar lid. The tension of the spring 20 can be varied by a screw likepiston l5, having a round disc I50. movable in a casing l3. The roller lI may be provided with a rubber covering H, to increase the frictionhold between it and the rollers B and 3. Thus the roller H is suitablyadjusted by the device l2, since it is disposed in the bite formed bythe roller 6 and roller 3. The knife 5 is thereby driven by the pressureroller 3 which in turn is driven by the roll 2. The screw 15 varies thefriction between rollers 6 and 3; hence, roll 2 controls roller 3 andcontrols the knife 5 by reason of the intermediate roller II. The roll 2of wound paper strips gradually increases in circumference and duringthat time is supported by rollers 30 and 3|, in the manner well known.

It is known, to rotate single circular knives for the cutting of paper.Heretofore, the circular knife or a pair of them was driven by means ofelectromotors with a cutter knife at one or both ends of the motorshaft. The objections are: the numerous motors are very expensive inregard to installation and upkeep, particularly on account of the numberrequired on large paper making machines. Furthermore, difliculties haveresulted from endeavoring to adjust the velocities of the knife andpaper. Heretofore, it was also customary to allow the knives to rotatewith uniform high velocities as the paper sheet had a high velocity toaccomplish the slitting automatically. For low velocity of the paper asit exists at the commencement of operations, this high velocity of theknives is not necessary, with the consequence that in comparison withthe work done in cutting, a comparatively high wear and tear on theknives took place.

Also difiiculties ensued in obtaining the high knife velocitiesnecessary for the high speed of the paper, which may be over 1200m aminute.

But the invention just described overcomes these Objections by themethod and means described, because the velocity of the knife isdependent directly upon the paper winding velocity. and because theknives are driven indirectly by the paper roll and in a ratio thereto.By this, the velocity of the knife is always in a certain ratio to thepaper velocity, so that, on the one hand, by low paper velocities, ahigh knife velocity is avoided with the loss of wearing of the knife,and on the other hand, with very high paper velocities, a very highvelocity is given to 10 the knife, so as to cut the paper efliciently.

I have described an embodiment of my invention, but changes may be madetherein without departing from the spirit of the invention as set forthin the appended claims.

I claim:

1. In a paper slitter, having a paper supply roll for supplying a papersheet, a circular knife for slitting the paper sheet, and a take-up rollfor the slitted sheet, the combination of an idler roll under said papersheet rotatable by the peripheral speed of the take-up roll, meanstransferring the peripheral speed of the idler roll to the knife forgiving the circular edge of the knife the same peripheral speed as thevelocity of the paper sheet being cut, and means for adjusting the lastnamed means.

2. In a paper slitter, having a paper supply roll for supplying a papersheet, a circular knife for slitting the paper sheet, and a take-up rollfor the slitted-sheet, the combination of an idler roll under said papersheet rotatable by the peripheral speed of the take-up roll, meanstransferring the peripheral speed of the idler roll to the knife forgiving the circular edge of the knife the same peripheral speed as thevelocity of the paper sheet being out, said means including a roll forthe circular knife and rotatable therewith. and a transfer rollperipherally contacting with the peripheral surface of the idler rolland with that of the knife roll, and means for adjusting the transferroll pressure upon the idler roll and upon the knife roll. I I

3. A paper cutting apparatus set forth in claim 1 wherein the adjustablemeans is a pair of members, one threaded within the other, theinnermember having a spring coa'cting between this member and the idlerroller mounting.

PAUL BAUR.

